Here are some softening tricks:
Won't is a contraction for will not, which may sound authoritative. Wouldn't can be softer than won't.
In the subject of the sentence, use inclusive plural (we, us) rather than the second person (you), which can sound more like an accusation.
Avoid embedding pronouns in a statement that make it sound more confrontational (like a you and a me).
After applying these three guidelines:
I won't want you to land up in the thread again to tell me the rules.
I wouldn't want us to land up in the thread again, discussing the rules.
Of course, all of these tricks are contextual; they work well when in the midst of a disagreement. I'm not saying to always avoid pronouns like you and me – yet I believe you're sharp enough to figure that out.